Package ai.libs.jaicore.logic.fol.util

Class ForwardChainer

java.lang.Object

ai.libs.jaicore.basic.algorithm.AAlgorithm<ForwardChainingProblem,java.util.Collection<java.util.Map<VariableParam,LiteralParam>>>

ai.libs.jaicore.logic.fol.util.ForwardChainer

All Implemented Interfaces:

ai.libs.jaicore.basic.algorithm.IAlgorithm<ForwardChainingProblem,java.util.Collection<java.util.Map<VariableParam,LiteralParam>>>, ai.libs.jaicore.basic.Cancelable, ai.libs.jaicore.basic.ILoggingCustomizable, java.lang.Iterable<ai.libs.jaicore.basic.algorithm.events.AlgorithmEvent>, java.util.concurrent.Callable<java.util.Collection<java.util.Map<VariableParam,LiteralParam>>>, java.util.Iterator<ai.libs.jaicore.basic.algorithm.events.AlgorithmEvent>

public class ForwardChainer
extends ai.libs.jaicore.basic.algorithm.AAlgorithm<ForwardChainingProblem,java.util.Collection<java.util.Map<VariableParam,LiteralParam>>>

This algorithm answers the question for which groundings G of the variables in $premise, G[$premise] follows from $factbase. This method does NOT adopt the closed world assumption, i.e. !L in the premise can only be followed if L is provably wrong in the factbase.

Constructor Summary

Constructors

Constructor	Description
ForwardChainer(ForwardChainingProblem problem)

Method Summary

Modifier and Type	Method	Description
java.util.Collection<java.util.Map<VariableParam,LiteralParam>>	call()
boolean	doesConclusionContainAGroundLiteralThatIsNotInFactBase(java.util.Collection<Literal> factbase, java.util.Collection<Literal> conclusion)
boolean	doesCWADeductionFail(java.util.Collection<Literal> factbase, java.util.Collection<Literal> conclusion)
java.util.List<java.util.Map<VariableParam,LiteralParam>>	getGroundingsUnderWhichALiteralAppearsInFactBase(java.util.Collection<Literal> factbase, Literal l, int maxSubstitutions)
java.util.Collection<java.util.Map<VariableParam,LiteralParam>>	getSubstitutionsThatEnableForwardChaining(java.util.Collection<Literal> factbase, java.util.Collection<Literal> conclusion)
NextBindingFoundEvent	nextBinding()
ai.libs.jaicore.basic.algorithm.events.AlgorithmEvent	nextWithException()
boolean	verifyThatGroundingEnablesConclusion(java.util.Collection<Literal> factbase, java.util.Collection<Literal> conclusion, java.util.Map<VariableParam,LiteralParam> grounding)

Methods inherited from class ai.libs.jaicore.basic.algorithm.AAlgorithm

activate, announceTimeoutDetected, avoidReinterruptionOnShutdownOnCurrentThread, cancel, checkAndConductTermination, checkTermination, computeTimeoutAware, getActivationTime, getConfig, getId, getInput, getLoggerName, getNumCPUs, getRemainingTimeToDeadline, getState, getTimeout, getTimeoutPrecautionOffset, hasNext, hasThreadBeenInterruptedDuringShutdown, interruptThreadAsPartOfShutdown, isCanceled, isShutdownInitialized, isStopCriterionSatisfied, isTimeouted, iterator, next, post, registerActiveThread, registerListener, resolveShutdownInterruptOnCurrentThread, setConfig, setLoggerName, setMaxNumThreads, setNumCPUs, setState, setTimeout, setTimeout, setTimeoutPrecautionOffset, shutdown, terminate, unregisterActiveThread, unregisterThreadAndShutdown

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Constructor Detail

ForwardChainer

public ForwardChainer(ForwardChainingProblem problem)

Method Detail

nextWithException

public ai.libs.jaicore.basic.algorithm.events.AlgorithmEvent nextWithException()
                                                                        throws java.lang.InterruptedException,
                                                                               ai.libs.jaicore.basic.algorithm.AlgorithmExecutionCanceledException,
                                                                               ai.libs.jaicore.basic.algorithm.exceptions.AlgorithmTimeoutedException

Throws:

java.lang.InterruptedException

ai.libs.jaicore.basic.algorithm.AlgorithmExecutionCanceledException

ai.libs.jaicore.basic.algorithm.exceptions.AlgorithmTimeoutedException

call

public java.util.Collection<java.util.Map<VariableParam,LiteralParam>> call()
                                                                           throws java.lang.InterruptedException,
                                                                                  ai.libs.jaicore.basic.algorithm.AlgorithmExecutionCanceledException,
                                                                                  ai.libs.jaicore.basic.algorithm.exceptions.AlgorithmTimeoutedException

Throws:

java.lang.InterruptedException

ai.libs.jaicore.basic.algorithm.AlgorithmExecutionCanceledException

ai.libs.jaicore.basic.algorithm.exceptions.AlgorithmTimeoutedException

nextBinding

public NextBindingFoundEvent nextBinding()
                                  throws java.lang.InterruptedException,
                                         ai.libs.jaicore.basic.algorithm.AlgorithmExecutionCanceledException,
                                         ai.libs.jaicore.basic.algorithm.exceptions.AlgorithmTimeoutedException

Throws:

java.lang.InterruptedException

ai.libs.jaicore.basic.algorithm.AlgorithmExecutionCanceledException

ai.libs.jaicore.basic.algorithm.exceptions.AlgorithmTimeoutedException

getSubstitutionsThatEnableForwardChaining

public java.util.Collection<java.util.Map<VariableParam,LiteralParam>> getSubstitutionsThatEnableForwardChaining(java.util.Collection<Literal> factbase,
                                                                                                                       java.util.Collection<Literal> conclusion)

doesConclusionContainAGroundLiteralThatIsNotInFactBase

public boolean doesConclusionContainAGroundLiteralThatIsNotInFactBase(java.util.Collection<Literal> factbase,
                                                                      java.util.Collection<Literal> conclusion)

doesCWADeductionFail

public boolean doesCWADeductionFail(java.util.Collection<Literal> factbase,
                                    java.util.Collection<Literal> conclusion)

Parameters:

factbase -

conclusion -

Returns:

true iff the conclusion contains a positive ground literal that is NOT in the factbase or a negative ground literal that positively occurs in the factbase

getGroundingsUnderWhichALiteralAppearsInFactBase

public java.util.List<java.util.Map<VariableParam,LiteralParam>> getGroundingsUnderWhichALiteralAppearsInFactBase(java.util.Collection<Literal> factbase,
                                                                                                                        Literal l,
                                                                                                                        int maxSubstitutions)

verifyThatGroundingEnablesConclusion

public boolean verifyThatGroundingEnablesConclusion(java.util.Collection<Literal> factbase,
                                                    java.util.Collection<Literal> conclusion,
                                                    java.util.Map<VariableParam,LiteralParam> grounding)